GraphQL

What is GraphQL?

GraphQL is an API technology originally developed by Facebook that enables clients to define the shape of the data they want. Instead of multiple endpoints returning fixed responses, GraphQL exposes a single endpoint where clients send queries specifying fields, relationships, and filters. This approach reduces over-fetching and under-fetching compared to traditional REST APIs.

Why GraphQL matters

GraphQL is widely adopted because it:

• Improves performance by minimizing payload size
• Simplifies frontend development with predictable responses
• Enables rapid iteration without changing backend endpoints
• Works well with modern SPAs, mobile apps, and microservices

In large systems, GraphQL can significantly reduce network chatter and client complexity.

Core GraphQL concepts

Key building blocks include:

• Schema – defines types, fields, and relationships
• Query – reads data
• Mutation – creates, updates, or deletes data
• Subscription – real-time data updates
• Resolver – backend function that fetches requested data

The schema acts as a contract between client and server.

GraphQL vs REST

Aspect	REST	GraphQL
Endpoints	Multiple	Single
Data shape	Server-defined	Client-defined
Over-fetching	Common	Minimal
Versioning	Often required	Usually unnecessary
Tooling	Mature	Mature, schema-driven

GraphQL does not replace REST in all cases; both often coexist.

GraphQL security considerations

Because GraphQL is flexible, it introduces specific risks:

• Excessive data exposure if schemas are too permissive
• Introspection abuse revealing API structure
• Expensive queries leading to denial-of-service
• Broken authorization at field or object level

Security must be enforced per field and per resolver, not only at the endpoint.

Securing GraphQL APIs

Best practices include:

• Strong authentication (OAuth, JWT, mTLS)
• Fine-grained authorization at resolver level
• Query depth and complexity limits
• Disabling or restricting introspection in production
• Input validation and schema hardening
• Centralized logging and monitoring

GraphQL security is a key part of API security strategy.

GraphQL in enterprise environments

GraphQL is commonly used for:

• Frontend aggregation across microservices
• Mobile and web applications
• Developer platforms and internal tooling
• Headless CMS architectures (including Strapi)

Many organizations use GraphQL as a BFF (Backend for Frontend) layer.

Common misconceptions

• "GraphQL is insecure by default"
• "GraphQL replaces REST entirely"
• "One endpoint means no access control"
• "GraphQL is only for frontend developers"